Terabit per second packet switch having distributed out-of-band control of circuit and packet switching communications

Abstract

A telecommunications switch which has a central switch fabric made up of multiple crossbars that can be used to switch either circuit switched or packet switch communications as long as appropriate input and output interfaces and controllers are provided. Thus, a large, high throughput telecommunications switch is provided where the expensive switch fabric core can remain the same and the interfaces and control cards changed as the relative demands for circuit switched communications and packet switched communications, such as ATM, evolve. Besides being flexible, this switch may also be fault tolerant.

What is claimed is: 
     
       1. A packet switch for switching circuit switched communications from a plurality of circuit switched input lines to a plurality of circuit switched output lines and packet switched communications from a plurality of packet switched input lines to a plurality of packet switched output lines, comprising: a plurality of circuit switched input interfaces, each having an input port connected to a respective circuit switched input line of said plurality of circuit switched input lines, and each of said circuit switched input interfaces having an output port;   a plurality of packet switched input interfaces, each having an input port connected to a respective packet switched input line of said plurality of packet switched input lines, and each of said packet switched input interfaces having an output port;   a single stage switch fabric having a plurality of input ports with a first portion of said input ports connected to respective output ports of said circuit switched input interfaces and a second portion of said input ports connected to respective output ports of said packet switched input interfaces;   a plurality of circuit switched output modules, said circuit switched output modules together having a plurality of inputs, each of said circuit switched output module inputs connected to respective output port of said first portion of said single stage switching fabric, and together having a plurality of outputs, each of said circuit switched output module outputs connected to a respective circuit switched output line of said plurality of circuit switched output lines;   a plurality of packet switched output modules, said packet switched output modules together having a plurality of inputs, each of said packet switched output module inputs connected to respective output port of said second portion of said single stage switching fabric, and together having a plurality of outputs, each of said packet switched output module outputs connected to a respective packet switched output line of said plurality of packet switched output lines;   means for hunting a path through said switch fabric to a desired circuit switched output line for communication on each circuit switched input line; and   means for hunting a path through said switch fabric to a desired packet switched output line for a packet on each packet switched input line.   
     
     
       2. The switch as set forth in claim 1, wherein: said circuit switched communication path hunting means includes a first out of band, controller; and   said packet switched communication path hunting means includes a second out of band, controller.   
     
     
       3. The switch as set forth in claim 2, wherein said switch fabric is partitioned into multiple pipes. 
     
     
       4. The switch as set forth in claim 3, wherein said out-of-band controllers roll requests which have been denied a path through a first pipe to a second pipe. 
     
     
       5. The switch as set forth in claim 3, wherein said out-of-band controllers roll requests which have been denied a path through a first pipe and a second pipe to a third pipe. 
     
     
       6. The switch as set forth in claim 3, wherein said out-of-band controllers roll requests which have been denied a path through a first pipe, a second pipe and a third pipe to a fourth pipe. 
     
     
       7. The switch as set forth in claim 3, wherein said second out-of-band controller assigns an order of preference to communication packets. 
     
     
       8. The switch as set forth in claim 1, wherein a size of said first portion of said switch fabric is in a range of zero to one hundred per cent. 
     
     
       9. The switch as set forth in claim 8, wherein a length of each communication packet may vary from one packet to another. 
     
     
       10. The switch as set forth in claim 1, wherein a length of each communication packet may vary from one packet to another. 
     
     
       11. A packet switch for switching a telecommunication packet from a plurality of input lines to a plurality of output lines, comprising: a plurality of input interfaces, each having an input port connected to a respective input line of said plurality of input lines, and each of said input interfaces having an output port;   a network for switching a plurality of I input ports to a plurality of P output ports;   each of said plurality of input interface output ports is fanned out to a respective group of F of said I input ports of said network;   said network having a plurality of C pipes, where C is an integer of a value equal to P/I;   a plurality of output modules, said output modules together having a plurality of inputs, each of said output module inputs connected to respective output port of said plurality of P output ports, and together having a plurality of outputs, each of said output module outputs connected to a respective output line of said plurality of output lines;   each pipe of said C pipes having a path from each of the plurality of inputs lines that is connectable to a respective output line of the plurality of output lines;   a spare pipe for on-line replacement of any one of said C pipes which is faulty; and   means for hunting a path through said packet switch for a telecommunication packet.